PDS APES 8th Period 2009-10

What’s that you say? You want to learn about Nuclear Power? I can help you with that. Let’s get started then!

Basics

What, exactly, is nuclear power? Well, it works like coal power in a lot of ways. It involves harnessing the energy (as heat) produced in a reaction to boil water and create steam that to spin a turbine, which in turn produces electricity. Although in the case of nuclear power, we harness the energy of a nuclear reaction (fission) as opposed to a chemical reaction like burning a fossil fuel. Overall, about 6% of the world’s energy needs are met with nuclear power, with around 400 active nuclear reactors on the planet.

http://en.wikipedia.org/wiki/File:Nuclear_fission.svg

Fission

The reaction that we use in nuclear power production is called fission. Fission involves firing a neutron at a large and unstable isotope. If the neutron collides with the nucleus of this unstable isotope, the isotope breaks into two fission fragments. This breaking apart of  the isotope releases a huge amount of energy, as well as a number of free, fast-moving neutrons. These neutrons can go on to collide with other unstable isotopes, causing them to break, a chain reaction. In nuclear power production, the unstable isotope of choice is Uranium-235, one of the three naturally occurring isotopes of Uranium on earth. Before it can be used as fuel, however, it must first be mined and refined. Maybe my friend Dr. Professor Ledgewick Brambleberry XXIII and his hideous assistant Jennings can help clarify:

What we know as nuclear power uses a controlled version of this reaction to produce steam. The reaction is controlled in a light-water reactor, and involves the use of control rods and water to keep the reaction from occurring too quickly.

http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/imgnuk/bwr.gif

Fusion

Theoretically, we could also use  nuclear fusionas a power source. Fusion is the reaction that occurs in the sun. In this process, two lighter elements (Hydrogen) fuse together under tremendous pressure at extremely high temperatures, forming a new nucleus of a heavier element such as Helium. We cannot, as of yet, actually create a controlled version of  this reaction. Once again, Dr. Professor Brambleberry:

Issues

One of the main concerns associated with nuclear power is radioactivity. Because the Uranium fuel used in fission is so unstable, it spontaneously decays. The products of this decay are harmful to humans, and can potentially cause burns or alter DNA. Nuclear decay can involve the release of alpha particles (two protons, two neutrons), beta particles (a free electron), and gamma rays (high-energy waves). These particle are released by the wastes of nuclear fission as well. Now to Jennings, once again.

Special thanks to Ian Noblitt for his part in the making of the videos.

Sources: Environmental Science: Problems, Concepts, and Solutions; 12th editionby G. Tyler Miller, Jr. and Scott Spoolman

I was sick with the Swine Flu for a bit during this unit, so I think I may have missed something in class. That or I did a bad job of studying.

Detritus:

What purposes does it serve? I know what it is, but I need a little help on why it is. It has a role in nutrient cycling, but how important is that role? The book says that detritus feeders use some of its nutrients, so does a lot go unused?

Also, where is it found? Every biome? Or is it more in forests? I can’t really picture detritus in alpine tundra…

Today we had a guest speaker in class, Garet Johnson from the Charlotte-Mecklenburg planning department. She spoke to us about urban planning and how it relates to our area.

Why do we need urban planning?

The Charlotte-Mecklenburg area has been growing pretty rapidly over the past few decades. It’s still undergoing considerable development, and the population is expected to continue to grow. So the city needs planners to help direct and manage this growth in a responsible way. Essentially, they act as policy advisors, helping City Council to make good, informed decisions while trying to handle this growth.

How does planning work in Charlotte?

As I mentioned earlier, the overall goal of urban planning is to figure out how best to deal with the growth of our city. We want to make sure that the city of Charlotte is a nice place to live in the future, so we have to guide how the city grows. This is accomplished through:

• Planning specific areas- Determining what is needed where and when it will be needed. What areas need homes? What areas need shopping? Where do we need schools? Parks? Where can we put industrial areas?The end result is a detailed guide to the development or re-development needed in certain areas. This is the part that planners do, and later on in class, we tried to do it.
• Zoning- Determining where certain kinds of things can go. The city doesn’t want industrial plants next-door to people’s houses, so it places restrictions on what can be built where. Since this is a legislative process, it’s the territory of City Council.

Centers, corridors, and wedges

The "Centers, Corridors, and Wedges" map

What is Charlotte’s overall plan? It’s more or less outlined in the handout called “Centers, Corridors, and Wedges” that we were given this week in class. It is the “growth framework” for the city.

• “Centers”- These are the hubs of activity in Charlotte. Places like Southpark or the Arboretum that are concentrated areas of industry or of commerce and entertainment.
• “Corridors”- These are the areas of Charlotte where the most growth is taking place. There are five of them, in a spoke-like pattern. They extend along major roads like I-77, I-85, and Independence.
• “Wedges”- These are primarily residential areas. On a map, they look like wedges between the corridors.

Some of the primary goals of the plan are:

• Connecting these different areas with mass transit like buses or light rail, and retrofitting the established automobile-centered system of roads to meet this goal
• Creating a better blend of these areas, and providing enough park space in all of them
• Encouraging “mixed-use” centers to cut down on the need for travel
• Building up, not out

Trying out some urban planning on a map.

Class Activity

Later in class, we broke into groups to try urban planning a bit for ourselves. We were given maps of the county and color-coded areas according to what we though should go there. The general class trend was creating mixed-use centers with residential, commercial, and entertainment areas all intermixed.

Links

Webpage for the city’s planning department: http://www.charmeck.org/Departments/Planning/Home.htm

“Centers, Corridors, and Wedges”   http://ww.charmeck.org/Planning/Land%20Use%20Planning/CentersCorridorsWedges/CentersCorridorsWedges(GrowthFramework_Draft).pdf

On page 131 in the textbook, Figure 7-8 lists Japan as a “stable” country in terms of population growth. But the video that we watched in class seemed to suggest that Japan’s population was declining and graying.
Do we know for sure if Japan is stable or declining? Or is it simply in one of the temporary declines that occur in a stable population? I know that a stable population has its ups and downs, so is it really necessary to treat a decline as inherently problematic? I use Japan as an example…this really applies to all countries in a similar situation.

Proof that I wasn’t making it up. As the textbook says, “some species form temporary groups for mating.” I’d say this is a pretty solid example.

So, I was wondering about the 5 Basic Causes of Environmental Problems listed in the book (p. 15). Specifically, I noticed that there’s no mentioning of Affluence as one of the 5 causes, despite it being a factor in I=PAT. There is, however, a section about both the damage it can do/benefits it can provide. Additionally, Poverty is listed as one of the 5 main causes. So I’ve got two main questions:

1. On the whole, which is more detrimental, Poverty or Affluence?
2. I know that Affluence can be both harmful and beneficial, but it tends to be more harmful, right? The pros don’t outweigh the cons?